Lazare Carnot at the Birth of the Modern Engineer in France
Carnot’s initiative gave engineers of France their mission in the 19th century to serve the public good through public works.
Carnot is a name that every engineer should know. Lazare and Sadi Carnot were the father and son who laid the scientific foundations for the industrial revolution at the beginning of the 19th century. Sadi is better known from his work on the Carnot Cycle, a fundamental concept in the science of thermodynamics. However, it was Lazare who has had the greater impact. Lazare Carnot introduced the concept of mechanical energy, which is essential for understanding how machines work. And, he played an important role in the birth of the modern engineer, the agent of progress during the 19th and 20th centuries.
The history of engineering spans the history of human civilization, but the 18th century stands out as a period of change in the profession. Before the 18th century engineers were artisans, highly skilled craftsmen, master builders and mechanics. The Marly Machine, constructed in 1684, was the ultimate achievement of medieval craft and mechanical know-how. Its fourteen gigantic water wheels raised water over 160 meters from to an aqueduct that supplied the fountains at Versailles, the palace of King Louis XIV located south of Paris. The engineer of the Marly Machine was Rennequin Sualem, a master carpenter and mechanic from Belgium.
But, at the same time that the Marley Machine was being built a different type of engineer was taking shape in the imagination of Sébastien Le Prestre de Vauban. Considered to be one of the greatest engineers of all time, Vauban built a system of fortifications to defend the borders of France. His fortification designs went beyond simply specifying the height and thickness of walls. Vauban also considered how the urban infrastructure would be arranged inside the fortification and how it would be supplied through the network of roads, bridges, and canals in the surrounding countryside. Over his career Vauban supervised the construction of over 300 fortifications. This work required organization and skills went beyond the craft of construction; it also required expertise in warfare, logistics, finance, and politics.
Vauban established a new organization within the army, the corps of engineers, to assure that there would be enough people capable of building and maintaining these fortifications. This was the first step in a transition in the engineering profession that continued through the 18th century. France established the first engineering school in 1748, the École royale du génie de Mézières to provide recruits entering the corps of engineers with an education in math, science, hydraulics, materials science, and the design of fortifications. By the middle of the 18th century, Vauban’s initiative had grown into three similarly organized groups: military engineers concerned with fortifications and artillery, navel engineers concerned with ships and ports, and the engineers of “ponts et chaussées” concerned with roads, bridges, and canals.[1]
The emergence of the modern engineer in France was not complete until the French Revolution (1789) brought engineers fully into the public sphere. Before the Revolution engineers served only the monarchy; they held the title of King’s Engineer. The Revolution brought an end to the monarchy. Everyone who formerly served the king scrambled to find a new mission appropriate to the republican government installed by the Revolution. Lazare Carnot was instrumental in guiding the corps of engineers through this transition.
Lazare Carnot was an 18th century military engineer who attained a position of great power in the revolutionary government. Carnot entered the corps of engineers in 1773 after graduating from the École royale du génie de Mézières. He became active in politics during the Revolution, and in 1793 he rose to serve as a member of the all powerful Committee of Public Safety under the government of the National Convention. Later, Carnot served as a Director under the French First Republic, and as Minister of War under Napoleon Bonaparte. Between political postings, Carnot produced important scholarly studies on mechanics, geometry, and calculus for which he was recognized by being elected to the Academy of Sciences.
Carnot was a reformer. He was known to his contemporaries as a serious person, principled, honest, tough-minded, but also an independent thinker and trouble-maker who was sometimes at odds with his superiors in the tradition-bound corps of engineers. As a young engineer, Carnot gained recognition and a certain degree of notoriety by winning a competition with an essay that celebrated the character and philosophy of Vauban. In this essay, Carnot describes the job of the military engineer in a way that undoubtedly reflected Carnot’s personal ideal:
The officer of engineers is in the midst of peril, but he is there alone and silent; […] he seeks the spot where the lightning burst forth, not to act, but to observe; not to get excited, but to deliberate.[2]
Carnot’s service on the Committee of Public Safety was a case the right man at the right time. Carnot was given responsibility for organizing the army and directing the defense of France. The remaining monarchies of Europe were alarmed at the ease by which revolutionaries were able to remove the French monarchy, which had existed for centuries, and they launched a military campaign against France to reverse the Revolution and contain its influence abroad. Carnot’s independence and progressive cast of mind enabled him to institute drastic measures required to reorganize the army, virtually overnight, from a professional army led by officers drawn from the aristocracy to an army of conscripts drawn from the general population. His success earned Carnot the title “Organizer of Victory.”
A major challenge confronting the Committee of Public Safety was simply finding people who could keep the country running. Aristocrats filled the high-level administrative positions in the government under the monarchy and served as officers in the army and the navy. Most aristocrats fled the country during the Revolution. Those who remained were regarded with suspicion, and many were thrown into prison and killed.
Carnot’s solution was to replace aristocrats with technocrats — people chosen for their knowledge and ability instead of their social standing, in short, engineers. In the world before the Revolution, which was characterized by social stratification and privileges granted to the aristocracy, the clergy, and the powerful craft guilds, the corps of engineers stood out as a self-governing body of people bound by their belief in meritocracy, science and rationality. Engineers did not suddenly take over the running of the country; for one thing there were not nearly enough of them. Rather, the engineer, as described by Carnot, served as a model for the ideal functionary of government.[3]
The Revolution created a crisis in the supply of engineers in France. At the same time that they were called to fill new rolls, the training of new engineers came to a halt. The royal engineering schools, which were established with the expressed purpose of producing Kings Engineers, did not survive the end of the monarchy. Carnot and Gaspard Monge, who had taught at the École royale du génie de Mézières, worked to create a new system of higher education that would fill the void left by closing the royal engineering schools. In 1794, Carnot and Monge, working with others, founded a new school, the Ecole Polytechnique.
The Ecole Polytechnique provided new recruits heading into different areas of engineering with a common base of knowledge in math and science, a role that this school continues to fill today. At the time of the Revolution the number of different types of engineers had grown to five; cartographic and mining engineers joined the military, naval, and roads and bridges identified in the middle of the 18th century. The Ecole Centrale des Arts et Manufactures, Gustave Eiffel’s alma mater, copied the polytechnic curriculum when it opened in 1829 to train engineers headed for work in industry. Through the 19th century new engineering schools opened in Europe and in the United States modeled on the Ecole Polytechnique. Today, science and mathematics form the core of the education for engineers everywhere in the world.
The Ecole Polytechnique was part of a broader initiative by Carnot to gather all the engineers in France under one overarching mission. In 1794, Carnot led a complete reorganization of the government that established public works (i.e. les travaux publics) as one of twelve principle functions of the national government, each administered by a separate commission. The Commission of Public Works was responsible for the national network of roads, bridges, canals, and ports, all fortifications and coastal defenses, and all government monuments and buildings.[4] One of the first actions taken by the Commission of Public Works, with Carnot’s encouragement, was to create the École Centrale des Travaux Publics, which became the Ecole Polytechnique in it second year of operation.
Thus, through Carnot’s initiative in establishing public works as a primary function of government and creating the Ecole Polytechnique, the engineers of France were given the mission to serve the public good through public works, broadly defined. This completed the transition that began with Sébastien Le Prestre de Vauban, the transition of engineering beyond the work of individual craftsmen into a modern profession based on a shared body of knowledge and expertise. Carnot’s description of Vauban, from his biographical essay on the great engineer, serves as well to describe the young engineers that the Ecole Polytechnique was intended to produce:
“[The engineer is] one of those men whom nature gives to the world formed entirely for benevolence; gifted, like the bee, with an innate activity for the general welfare; who cannot separate their lot from that of the Republic, and who, intimate members of society, live and flourish, or suffer and languish, with it.”[2]
Notes
[1] From the Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers published in 1751-1772 by Denis Diderot and Jean Le Rond d’Alembert.
[2] Quoted in: Arago, F., 1857. Biographies of Distinguished Scientific Men,
Longman, Brown, Green, Longmans, & Roberts, London.
[3] Alder, K., 2010. Engineering the Revolution: Arms and Enlightenment in France, 1763–1815, University of Chicago Press.
[4] Carnot, L. 1794. Décret, présenté par Carnot au nom du comité de salut public, remplaçant le Conseil exécutif provisoire par 12 Commissions exécutives, lors de la séance du 12 germinal an II (1er avril 1794), Archives Parlementaires de la Révolution Française Année 1968 87 pp. 697–699. [online: (accessed 4 Sep 2023) https://www.persee.fr/doc/arcpa_0000-0000_1968_num_87_1_21093_t1_0697_0000_5]
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